A048549
a(n+1) is next smallest prime beginning with a(n), initial prime is 2.
Original entry on oeis.org
2, 23, 233, 2333, 23333, 2333321, 233332117, 2333321173, 233332117313, 23333211731399, 2333321173139903, 2333321173139903173, 23333211731399031733, 2333321173139903173301, 2333321173139903173301021
Offset: 1
Similar to but different from
A069603.
-
b = 10; s = {{2}};
Do[NestWhile[# + 1 &, 0, ! (PrimeQ[FromDigits[tmp = Join[Last[s], (nn = #;
IntegerDigits[nn - Sum[b^n, {n, l = NestWhile[# + 1 &, 1, ! (nn - (Sum[b^n, {n, #}]) < 0) &] - 1}], b, l + 1])], b]]) &]; AppendTo[s, tmp], {20}]; Map[FromDigits, s] (* Peter J. C. Moses, Aug 06 2015 *)
A048556
p(n+1) is next smallest prime beginning with p(n), initial prime is 19.
Original entry on oeis.org
19, 191, 1913, 19139, 1913903, 19139039, 191390393, 19139039303, 1913903930321, 191390393032123, 1913903930321233, 191390393032123361, 19139039303212336171, 1913903930321233617139, 191390393032123361713943
Offset: 0
A048552
a(n+1) is next smallest prime beginning with a(n), initial prime is a(0) = 7.
Original entry on oeis.org
7, 71, 719, 7193, 71933, 719333, 71933317, 719333177, 71933317711, 7193331771103, 71933317711039, 7193331771103939, 719333177110393913, 7193331771103939133, 719333177110393913323, 71933317711039391332309, 719333177110393913323097, 719333177110393913323097047
Offset: 0
-
f:= proc(n) option remember; local q,d,v;
q:=procname(n-1);
for d from 1 do
v:= nextprime(q*10^d);
if v < (q+1)*10^d then return v fi
od
end proc:
f(0):= 7:
map(f, [$0..20]); # Robert Israel, Jan 26 2020
-
Nest[Function[{a, n}, Append[#, Catch@ Do[Do[If[PrimeQ@ #, Throw@ #; Break[], #] &@ FromDigits[n~Join~PadLeft[IntegerDigits[(5 j - 4 + Mod[3 j + 2, 4])/2], i]], {j, 4*10^(i - 1)}], {i, Infinity}]]] @@ {#, IntegerDigits[#[[-1]] ]} &, {7}, 17] (* Michael De Vlieger, Jan 26 2020 *)
-
next_A048552(p)=for(i=1,oo,my(q=nextprime(p*=10));q-p>10^i||return(q))
A048552(n,p=7)=vector(n,i,i>1&&p=next_A048552(p);p) \\ M. F. Hasler, Jan 26 2020
A048550
a(n+1) is the next smallest prime beginning with a(n), initial prime is 3.
Original entry on oeis.org
3, 31, 311, 3119, 31193, 3119309, 31193093, 311930933, 31193093317, 311930933179, 3119309331797, 311930933179703, 31193093317970371, 3119309331797037107, 311930933179703710759, 31193093317970371075907
Offset: 0
-
f:= proc(n) local d,a;
for d from 1 do
for a from 10^d*n+1 by 2 to 10^d*(n+1) do
if isprime(a) then return a fi
od od
end proc:
R:= 3: x:= 3:
for i from 2 to 30 do
x:= f(x);
R:= R, x;
od:
R; # Robert Israel, Dec 13 2023
Showing 1-4 of 4 results.